Pathologic Prostate Cancer Characteristics in Patients Eligible for Active Surveillance: A Head-to-Head Comparison of Contemporary Protocols

Histology core-specific evaluation of the European Society of Urogenital Radiology (ESUR) standardised scoring system of multiparametric magnetic resonance imaging (mpMRI) of the prostate

OBJECTIVES

To evaluate the Prostate Imaging Reporting and Data System (PIRADS) in multiparametric magnetic resonance imaging (mpMRI) based on single cores and single-core histology. To calculate positive (PPV) and negative predictive values (NPV) of different modalities of mpMRI.

PATIENTS AND METHODS

We performed MRI-targeted transrectal ultrasound-guided perineal prostate biopsies on 50 patients (mean age 66 years, mean PSA level of 9.9 ng/mL) with suspicion of prostate cancer. The biopsy trajectories of every core taken were documented in three dimensions (3D) in a 3D-prostate model. Every core was evaluated separately for prostate cancer and the performed biopsy trajectories were projected on mpMRI images. PIRADS scores of 1177 cores were then assessed by a histology 'blinded' uro-radiologist in T2-weighted (T2W), dynamic contrast-enhanced (DCE), diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS).

RESULTS

The PIRADS score was significantly higher in cores positive for cancer than in negative cores. There was a significant correlation between the PIRADS score and histopathology for every modality. Receiver operating characteristic (ROC) analysis showed excellent specificity for T2W (90% peripheral zone/97% transition zone) and DWI (98%/97%) images regardless of the prostate region observed. These numbers decreased for DCE (80%/93%) and MRS (76%/83%). All modalities had NPVs of 99%, if a PIRADS score threshold of 2 (for T2W, DCE, and MRS) or 3 (for DWI) was used. However, PPVs were low.

CONCLUSIONS

Our results show that PIRADS scoring is feasible for clinical routine and allows standardised reporting. PIRADS can be used as a decision-support system for targeting of suspicious lesions. mpMRI has a high NPV for prostate cancer and, thus, might be a valuable tool in the initial diagnostic evaluation.

Utility of multiparametric magnetic resonance imaging suspicion levels for detecting prostate cancer

PURPOSE

We determine the usefulness of multiparametric magnetic resonance imaging in detecting prostate cancer, with a specific focus on detecting higher grade prostate cancer.

MATERIALS AND METHODS

Prospectively 583 patients who underwent multiparametric magnetic resonance imaging and subsequent prostate biopsy at a single institution were evaluated. On multiparametric magnetic resonance imaging, lesions were identified and scored as low, moderate or high suspicion for prostate cancer based on a validated scoring system. Magnetic resonance/ultrasound fusion guided biopsies of magnetic resonance imaging lesions in addition to systematic 12-core biopsies were performed. Correlations between the highest assigned multiparametric magnetic resonance imaging suspicion score and presence of cancer and biopsy Gleason score on the first fusion biopsy session were assessed using univariate and multivariate logistic regression models. Sensitivity, specificity, negative predictive value and positive predictive value were calculated and ROC curves were developed to assess the discriminative ability of multiparametric magnetic resonance imaging as a diagnostic tool for various biopsy Gleason score cohorts.

RESULTS

Significant correlations were found between age, prostate specific antigen, prostate volume, and multiparametric magnetic resonance imaging suspicion score and the presence of prostate cancer (p<0.0001). On multivariate analyses controlling for age, prostate specific antigen and prostate volume, increasing multiparametric magnetic resonance imaging suspicion was an independent prognosticator of prostate cancer detection (OR 2.2, p<0.0001). Also, incremental increases in multiparametric magnetic resonance imaging suspicion score demonstrated stronger associations with cancer detection in patients with Gleason 7 or greater (OR 3.3, p<0.001) and Gleason 8 or greater (OR 4.2, p<0.0001) prostate cancer. Assessing multiparametric magnetic resonance imaging as a diagnostic tool for all prostate cancer, biopsy Gleason score 7 or greater, and biopsy Gleason score 8 or greater separately via ROC analyses demonstrated increasing accuracy of multiparametric magnetic resonance imaging for higher grade disease (AUC 0.64, 0.69, and 0.72, respectively).

CONCLUSIONS

Multiparametric magnetic resonance imaging is a clinically useful modality to detect and characterize prostate cancer, particularly in men with higher grade disease.

Expanded criteria to identify men eligible for active surveillance of low risk prostate cancer at Johns Hopkins: a preliminary analysis

PURPOSE

At our institution the eligibility criteria used to enroll patients in active surveillance are clinical stage T1, prostate specific antigen density less than 0.15 ng/ml, biopsy Gleason score 6 or less, 2 or fewer positive biopsy cores and 50% or less involvement of any biopsy core. We hypothesized that these criteria may be excessively strict, precluding many men from active surveillance.

MATERIALS AND METHODS

We studied pathological outcomes in men treated with radical prostatectomy between 1995 and 2012 who met 4 or more of the 5 active surveillance criteria. Outcomes included a definition of significant tumor (pathological Gleason 7 or greater, or nonorgan confined). We compared adverse pathology rates between men who met all 5 vs 4 of 5 active surveillance criteria.

RESULTS

Of 8,261 men 1,890 (22.9%) met all active surveillance eligibility criteria and 2,133 (25.8%) met 4. Men with values exceeding prostate specific antigen density and biopsy Gleason criteria were at increased risk for adverse pathological outcomes. Clinical stage greater than T1 was not associated with adverse pathological findings. The risk of significant tumors in men with clinical stage T2 lesions, 3 or fewer positive biopsy cores and less than 60% core involvement was comparable to that of men who met all active surveillance criteria.

CONCLUSIONS

Prostate specific antigen density greater than 0.15 ng/ml and biopsy Gleason score 7 or greater are strongly associated with adverse pathological findings at radical prostatectomy. Our findings suggest that active surveillance criteria should be expanded to include men with clinical stage T2 lesions and a greater number of positive biopsy cores of low grade. Based on these preliminary findings, we are in the process of reassessing active surveillance eligibility criteria using more detailed pathological analysis.

Timing of curative treatment for prostate cancer: a systematic review

CONTEXT

Delaying definitive therapy unfavourably affects outcomes in many malignancies. Diagnostic, psychological, and logistical reasons but also active surveillance (AS) strategies can lead to treatment delay, an increase in the interval between the diagnosis and treatment of prostate cancer (PCa).

OBJECTIVE

To review and summarise the current literature on the impact of treatment delay on PCa oncologic outcomes.

EVIDENCE ACQUISITION

A comprehensive search of PubMed and Embase databases until 30 September 2012 was performed. Studies comparing pathologic, biochemical recurrence (BCR), and mortality outcomes between patients receiving direct and delayed curative treatment were included. Studies presenting single-arm results following AS were excluded.

EVIDENCE SYNTHESIS

Seventeen studies were included: 13 on radical prostatectomy, 3 on radiation therapy, and 1 combined both. A total of 34 517 PCa patients receiving radical local therapy between 1981 and 2009 were described. Some studies included low-risk PCa only; others included a wider spectrum of disease. Four studies found a significant effect of treatment delay on outcomes in multivariate analysis. Two included low-risk patients only, but it was unknown whether AS was applied or repeat biopsy triggered active therapy during AS. The two other studies found a negative effect on BCR rates of 2.5-9 mo delay in higher risk patients (respectively defined as any with T ≥ 2b, prostate-specific antigen >10, Gleason score >6, >34-50% positive cores; or D'Amico intermediate risk-group). All studies were retrospective and nonrandomised. Reasons for delay were not always clear, and time-to-event analyses may be subject to bias.

CONCLUSIONS

Treatment delay of several months or even years does not appear to affect outcomes of men with low-risk PCa. Limited data suggest treatment delay may have an impact on men with non-low-risk PCa. Most AS protocols suggest a confirmatory biopsy to avoid delaying treatment in those who harbour higher risk disease that was initially misclassified.